This invention relates to the fields of dielectrokinesis (phoresis), dielectric relaxation dynamics, electronic devices and systems and, more particularly, to a selective polarization matching filter for triggering and maximizing the dielectrokinesis response in the detection of specific entities consisting of organic and inorganic materials via detection of a force or replenishment energy density of stored electrical energy.
The detection of the presence or absence of specific entitiesxe2x80x94human beings, plastics (mixtures of various polymers and with additives) and other organic/inorganic materialsxe2x80x94irrespective of the presence of intervening vision-obstructing structures or EMI signals has uses in very diverse applications such as: (a) fire fighting and rescue; (b) national border security; (c) transportation security in pre-boarding planes, trains and automobiles; (d) new and old construction industry; (e) law enforcement; (f) military operations; (g) anti-shoplifting protection; (h) other security and emergency needs and operations, etc.
It is known that humans, animals and other animate species generate an external electric field and gradients thereof. For example, in human physiology, the central and peripheral nervous system neurons, the sensory system cells, the skeletal muscular system, as well as the cardiac conduction cells and cardiac muscle system cells all operate by a depolarization and repolarization phenomena occurring across their respective cellular membranes, which are naturally in a dielectric polarization state.
The trans-membrane ion currents and potentials utilizing Na+1, K+1 ions, etc., all work to establish a resting potential across the cell membranes that can be characterized as a high state of polarization. The ion concentration (moles/cm3) within and surrounding the unmyelinated cell axon establish the resting potential. The fluids themselves are neutral. What keeps the ions on the membrane is their attraction for each other across the membrane. Independent of this process the Clxe2x88x921 ions tend to diffuse into the cell since their concentration outside is higher. Both the K+1 and Clxe2x88x921 diffusion tend to charge the interior of the cell negatively and the exterior of the cell positively. As charge accumulates on the membrane surface, it becomes increasingly difficult for more ions to diffuse. K+1 ions trying to move outward are repelled by the positive charge already present. Equilibrium is reached when the tendency to diffuse because of the concentration is balanced by the electrical potential difference across the membrane. The greater the concentration difference, the greater the potential difference across the membrane. The resting potential can be calculated by the Nernst Equation, wherein the potential (V)=VInsidexe2x88x92VOutside such that:       Voltage    ⁡          (      potential      )        =      2.30    ⁢          xe2x80x83        ⁢          kT      ze        ⁢          xe2x80x83        ⁢    log    ⁢          xe2x80x83        ⁢          Co      Ci      
where Co and Ci are ion concentrations inside and outside, k is the Boltzmann constant, T is absolute temperature, e is the charge on the electron and z is the valence (number of electron charges) on the ion.
The nerve and conduction impulses, as well as the sensory, cardiac, and muscular action potentials and subsequent responses are manifested via sequential periodic pulses (waves) resulting in first rapid depolarization and, shortly after, rapid repolarization to reestablish the rest state, namely, the original polarization state of the membrane. The transverse membrane ion currents produce a dipole charge that moves along the cell membrane. The greater the stimulus the more the pulses that are produced along the membrane.
The action potentials are related to the ratio of the respective ion concentrations inside and outside the different types of membranes. The resultant polarization electrical field distribution pattern has a high degree of spatial non-uniformity and can be characterized as a bound dipolar charge distribution pattern. A detailed discussion of the human generated electric field can be found in R. A. Rhodes, Human Physiology, Harcourt Brace Javanovich (1992) and D. C. Gianocoli, Physics Principles with Applications, Prentice Hall (1980), the teachings of which are hereby incorporated by reference.
Alternatively, the external electric field and gradients thereof can be supplied by an external source via static electrification for use with inanimate targets such as plastics, metals, water, etc.
It would be advantageous to be able to detect the external electric field and gradients thereof, either generated naturally by an animate species or induced by an external source, on an entity specific basis. It would further be advantageous to enable this detection at great distances and through obstructions. It has been discovered that such detection is possible using the selective polarization matching filter in accordance with the present invention in conjunction with the principles of dielectrophoresis.
Dielectrophoresis describes the force upon and mechanical behavior of initially neutral matter that is dielectric polarization charged via induction by external spatially non-uniformity electric fields. The severity of the spatial non-uniformity of the electric field is measured by the spatial gradient (spatial rate of change) of the electric field. A fundamental operating principle of the dielectrophoresis effect is that the force (or torque) in air generated at a point and space in time always points (or seeks to point) in the same direction, mainly toward the maximum gradient (non-uniformity) of the local electric field, independent of sign (+ or xe2x88x92) and time variations (DC or AC) of electrical fields (voltages) and of the surrounding medium dielectric properties.
The dielectrophoresis force magnitude depends distinctively nonlinearly upon the dielectric polarizibility of the surrounding medium, the dielectric polarizibility of initially neutral matter and nonlinearly upon the neutral matter""s geometry. This dependence is via the Clausius-Mossotti function, well-known from polarizibility studies in solid state physics. The dielectrophoresis force depends nonlinearly upon the local applied electric field produced by the target. The dielectrophoresis force depends upon the spatial gradient of the square (second power) of the target""s local electric field distribution at a point in space and time where a detector is located. The spatial gradient of the square of the local electric field is measured by the dielectrophoresis force produced by the induced polarization charge on the detector. This constant-direction-seeking force is highly variable in magnitude both as a function of angular position (at fixed radial distance from the target) and as a function of the radial position (at a fixed angular position) and as a function of the xe2x80x9ceffectivexe2x80x9d medium polarizibility. The force""s detection signature is a unique pattern of the target""s spatial gradient of the local electric field squared, with the detector always pointing (seeking to point) out the direction of the local maximum of the gradient pattern. All experimental results and equations of dielectrophoresis are consistent with the fundamental electromagnetic laws (Maxwell""s equations).
It is conventional for initially neutral matter to exhibit regular xe2x80x9cpara-electricxe2x80x9d (closely related to) phenomena called dielectrophoresis (i.e., force and torque pivots the initially neutral matter to align itself with the spatial position of the local maximum spatial gradient of the external electric field squared), however, this need not always be the case. The normal para-electric dielectrophoresis response is generally the result of a two-step process: (1) induced polarization of the initially neutral matter by the external electric field pattern, followed by (2) action of the spatially non-uniform external electric field pattern upon the induced dipole within the neutral matter to produce a conventional para-electric dielectrophoresis force and torque rotating the neutral matter around a pivot line in order to align the long dimension of the neutral matter with the spatial position of the maximum spatial gradient of the external electric field squared.
An exact opposite operative mode of the dielectrophoresis phenomena occurs, an unconventional xe2x80x9capo-electricxe2x80x9d (away from; separate) electric dielectrophoresis force and torque can arise if, for example, the initially neutral matter has already been both (1) previously strongly pre-polarized (e.g., permanent dipole ferroelectric material (such as BaTiO3, PbTiO3 or BaxSryTiO3 (where x+y=1), etc.) or a long lasting dipole electret material (such as Carnauba wax, Teflon(trademark) (polytetrafluoroethylene), or Mylar(trademark) (polyethyleneterephthalate), etc.) both made by xe2x80x9cpolingxe2x80x9d or subjecting the neutral matter to a strong external DC voltage with or without an external, elevated temperature) and (2) the neutral matter is being spun about an axis of rotation. The apo-electric dielectrophoresis force and torque rotates the xe2x80x9cpoledxe2x80x9d neutral matter around a pivot line in order to align the long dimension of the neutral matter with the spatial position of the local minimum spatial gradient of the external electric field squared. The apo-electric response is self-extinguishing in that, when the xe2x80x9cpoledxe2x80x9d neutral matter is made to stop spinning, the poled neutral matter now exhibits para-electric dielectrophoresis phenomena (force, torque) in exactly the same operative mode as exhibited by non-poled, non-prepolarized neutral matter (rotation to point toward the local maximum spatial gradient of the external electric field squared).
The unconventional apo-electric dielectrophoresis response is the strongest when the axis of rotation of the ferroelectric or electret material is at a right angle to the external electric field direction. The apo-electric dielectrophoresis response is negligible if the axis of rotation is parallel to the external field direction. The apo-electric response will thus occur only for the component of the external electric field perpendicular to the axis of rotation. The application of an external electric field to a material system capable of making an unconventional, apo-electric dielectrophoresis response increases the energy state of the system. The application of para-electric dielectrophoresis response decreases the energy state of the system. The source of energy in both situations is the entity (human operator) providing the spinning of the poled materials and sampling of the external electric field spatial gradient pattern.
The apo-electric unconventional dielectrophoresis response, although predicted many years ago has not yet been observed for macroscopic bodies (like humans), H. A. Pohl, J. Electrochemical Society, 115, 155c (1968). On the molecular size scale, for example, an apo-electric dielectrophoresis-type response is used in a vital step in the maser/laser operation to artificially shift the population of excited states before the masing/lasing effect begins (C. H. Townes, Science, 149, 831 (1965)).
There are five known modes of dielectric polarization. These include: electronic polarization, where electron distribution about the atom nuclei is slightly distorted due to the imposed external electric field; atomic polarization, where the atom""s distribution within initially neutral matter is slightly distorted due to the imposed external electric field; nomadic polarization, where in very specific polymers, etc., highly delocalized electron or proton distribution is highly distorted over several molecular repeat units due to the imposed external electric field; rotational polarization (dipolar and orientational), where permanent dipoles (H2O, NO, HF) and orientable pendant polar groups (xe2x80x94OH, xe2x80x94Cl, xe2x80x94CN, xe2x80x94NO2) hung flexibly on molecules in material are rotationally aligned toward the external electric field with characteristic time constants; and interfacial (space charge) polarization, where inhomogeneous dielectric interfaces accumulate charge carriers due to differing small electrical conductivities. With the interfacial polarization, the resulting space charge accumulated to neutralize the interface charges distorts the external electric field with characteristic time constants.
The first three modes of dielectric polarization, electronic, atomic and nomadic, are molecular in distance scale and occur xe2x80x9cinstantaneouslyxe2x80x9d as soon as the external electric field is imposed and contribute to the dielectric constant of the material at very high frequencies (infrared and optical). The last two polarization modes, rotational and interfacial, are molecular and macroscopic in distance scale and appear dynamically over time with characteristic time constants to change (usually increase) the high frequency dielectric response constant toward the dielectric constant at zero frequency. These characteristic material time constants control the dielectric and mechanical response of a material.
The modes of polarization and their dynamics in contributing to the time evolution of dielectric constants are discussed in various publications, such as H. A. Pohl, Dielectrophoresis, Cambridge University Press (1978); R. Schiller Electrons in Dielectric Media, C. Ferradini, J. Gerin (eds.), CRC Press (1991), and R. Schiller, Macroscopic Friction and Dielectric Relaxation, IEEE Transactions on Electrical Insulation, 24, 199 (1989). See also, Herbert A. Pohl, Dielectrophoresis: The Behavior of Neutral Matter in Non-Uniform Electric Fields, Cambridge University Press (1978). A. D. Moore (Editor), Electrostatics and its Applications, Chapters 14 and 15 (Dielectrophoresis), Wiley/Interscience (1973), pages 336-376. These teachings are hereby incorporated by reference.
The present invention relates to a modified selective polarization matching filter formed of compositions of matter using a pre-polarization (xe2x80x9cpoledxe2x80x9d or previously subjected to a strong external DC voltage with or without an external, elevated temperature) step, converting the initially neutral material into an electret state with long-lasting polarization (weeks/months/years) or into a ferroelectric state with permanent polarization. The composition of matter serves as a dielectric replicate matching reference material that is used to make a detection device component that triggers and maximizes, when the poled, pre-polarized material/component is also subject to externally initiated spinning (set in rotary motion), an apo-electric dielectrokinesis (phoresis) phenomena (force, torque) occurring in an exact opposite operative mode of the dielectrophoresis phenomena to that which occurs when the component and material are not pre-polarized (poled), and a conventional para-electric dielectrokinesis (phoresis) phenomena occurs, where both operative modes can be used to detect the presence of specific entities of a predetermined type that contain as a major component the matching dielectric material (poled or non-poled). The modified, selective polarization filter is an important element in triggering and also maximizing both the mechanical torque and energy replenishment modes using dielectrokinesis (phoresis) methods to detect entities.
The exact opposite operative mode of the dielectrokinesis phenomena exhibited by the poled material or component is self-extinguishing in that, when placed in a specific detection device, and the poled component is not spinning, the poled component exhibits dielectrokinesis (force, torque) in exactly the same operative mode as that exhibited by non-poled, non-pre-polarized components. Different designs and materials of construction for the detection device component enable the detection of a variety of specific entities including human beings, animals, plastics, metals, water, etc. Detectors are effective using specific combinations of poled and non-poled components and materials irrespective of the presence or absence of any type of intervening visual obstructing material structures or barriers, lighting or weather conditions or electromagnetic interference (EM).
A non-poled selective polarization matching filter of the copending application noted above is formed of compositions of matter using initially neutral material chosen to be an exact dielectric replicate of an entity to be detected via dielectrokinesis (phoresis). The filter is an important element in triggering and also maximizing both the mechanical torque and energy replenishment modes using dielectrokinesis (phoresis) methods to detect entities.
This filtering action of either construction applies to a practically limitless range of materials to be detected as an entity of interest target. The detection materials include, for example, nano-structured human keratin protein polymer for human detection, nano-structured animal keratin protein polymer for animal detection, specific plastic (mixture of polymers and additives) for plastic detection, and the like. The dielectric replicate material comprising the selective polarization filter functionally performs a spatial dielectric property matching between the entity of interest and a locator device to locate the entities. The filter enables the device to operate using the dielectrokinesis (phoresis) phenomena to specifically detect only those entities matching the dielectric response signature of the polarization filter component. The dielectric signature includes both the dielectric constant and dielectric loss frequency spectra and all characteristic time constants controlling the polarization evolution/mechanics in external electric fields.
There are two primary elements for the dielectrokinesis entity location detection device to operate. The first element is an external electric field and spatial gradients thereof, and the second element is the selective dielectric polarization matching filter of the present invention. As noted above, the external electric field and gradients thereof can be provided by the entity of interest itself as is the case when animate species are the entities of interest to be detected. Alternatively, the external electric field and gradients thereof can be supplied by an external source via static electrification as is the case when inanimate entities are the entities of interest to be detected.
The selective polarization matching filter embodied in this invention can be used in the detection device itself as either a passive or active circuit component (no flowing or flowing continuous electric current, respectively). The selective polarization matching filter embodied in this invention can be used with conventional electronic components (resistors, capacitors, inductors, transistors, etc.) in the overall operational design of the type of locator device used to detect the presence or absence of a specific entity of a predetermined type.